Rolled strip materials with a continuously varying thickness, that is, variable thickness plates, are currently promoted in the automobile industry to produce lightweight automobiles. As shown in FIG. 1, such a variable thickness plate can be obtained by sheet rolling or coil rolling, and is generally produced by using the more efficient coil rolling method in the industry.
Plate materials are required to be corrosion resistant in some application scenarios. Therefore, some variable thickness plates must be supplied in a galvanized form. Galvanization includes hot-dip galvanization and electrogalvanization. Hot-dip galvanization is more cost-effective and environmentally-friendly than electrogalvanization.
Several existing production methods are as follows:
In a production process used in the patent CN 101796210.B, a hot-rolled steel strip is first hot-dip galvanized or hot-dip aluminized and then rolled with a continuously varying thickness. Subsequently, plate materials needed by a user are cut from a steel coil as required.
In a method used in the patent CN 103806029.A, a strip material is flexibly rolled, then electroplated, then alloyed, and delivered to a user for shaping.
In a method proposed in the patent U.S. Pat. No. 8,522,586B2, a hot-rolled or cold-rolled starting material is hot-dip coated or electroplated and then flexibly rolled. Subsequent processes are then performed.
In the patent CN 102712961, a hot-rolled starting material is flexibly rolled, then subjected to recrystallization annealing, then electroplated, and alloyed.